Preeclampsia (PE) is a pregnancy-induced hypertensive disorder without an effective treatment. The goal of this project is to produce a safe and effective biologic for treatment of very preterm PE. PE is the leading cause of pregnancy-related morbidity and mortality in the US, affecting over 200,000 pregnant women and newborns annually, at a significant cost to the healthcare system and lifelong consequences. PE is characterized by the new onset of hypertension and can lead to more serious complications, such as seizure (eclampsia) and HELLP syndrome associated with systemic organ failure and death. Current interventions to treat PE include magnesium sulfate as an anticonvulsant and antihypertensive drugs, which may manage symptoms but do not target the underlying causes of the disease. One potential cause of PE is an imbalance of angiogenic factors, specifically antiangiogenic sFlt1 and proangiogenic PlGF. Higher sFlt1:PlGF ratios correlate with increased severity of disease and poor clinical outcome. The product of this SBIR will be recombinant human PlGF protein (rhPlGF) as a replacement therapy to treat very preterm PE and prolong pregnancy without adverse maternal or fetal effects. The long term goal is to develop and commercialize a safe therapeutic for very preterm PE to improve health outcomes by reducing maternal symptoms and extending fetal gestation toward >34 weeks. For SBIR Phase I, we successfully 1) expressed and purified rhPlGF then demonstrated that rhPlGF can bind endogenous free sFlt1 in PE serum in vitro, and 2) showed efficacy in the RUPP rat model of PE in vivo, as rhPlGF restored circulating free sFlt1, blood pressure and renal function towards normal pregnant levels. For SBIR Phase II, we will 1) demonstrate that rhPlGF can be safely administered in third trimester pregnant non-human primates without toxicity, and 2) complete a cGMP manufacturing campaign for use in a Phase I clinical study. After the SBIR Phase II, Aggamin has plans for a clinical trial partnership and commercialization with an established pharmaceutical company. PE affects 3-8% of all pregnancies and disease incidence is rising as risk factors such as obesity, diabetes, women?s age at pregnancy, and rate of multiple births increase. The market for Aggamin?s treatment for preterm PE cases, evident before 34 weeks, is estimated at up to 60,000 patients worldwide, and could later increase to include PE cases where symptoms appear after 34 weeks. Reimbursement rates will be justified by reducing or eliminating neonatal ICU costs and improving health outcomes for the newborn and mother. The total market for Aggamin?s therapeutic product to treat very preterm PE cases in the US is estimated at $0.5-1.5 billion. The rhPlGF replacement therapy will be a first-in-class treatment for PE, and if proven safe and effective, its medical and commercial value will be substantial.